Fauquet, Claude

Lamy

Thouvenel, Jean-Claude

Horizon / Pleins textes

TWO VIRAL DISEASES OF PSOPliOCPRPUS TETRAGOI?OLOBUS 
IDENTIFIED I N  IVORY-COAST 
FAUQUET C, LAIì! D., THOWENEL J.-C.  
Virology department 
QRSTOM BP V 5 1  
Abidjan, Côte d ' I v o i r e  
INTRODUCTION. The winged-bean i s  a backyard crop (Pscphocarpus tetragonoZobus) grown 
i n  Southeast Asia from Papua t o  S r i  Lanka. It i s  a leguminous p l a n t  that  i s  v e r y  
r i c h  i n  p r o t e i n s  e i t h e r  i n  th2  seeds (30/37 X), t u b e r s  (12/15 W), leaves (6/15 XI 
o r  flowers !5/6 %>. The immature pcds are very r i c h  i n  vi tamins and the  seeds  
are a source of e d i b l e  o i l  (15/20 Z f a t ) ,  
In 1975 a pane l  of t h e  Nat ional  Academy o f  Sciences i n  Washington, 
concerning unde rexp lo i t ed  t r o p i c a l  p l a n t s  recognized i t s  i n t e r e s t  as a food crop ' 
through t h e  humid t r o p i c a l  zone, where i t  can h e l p  so lve  t h e  problem of malnu- 
t r i t i o n .  The pane l  counsel led t e s t i n g  the  p l a n t  i n  experimental  s t a t i o n s  i n  
di . f ferent  regions of t h e  t r o p i c s .  I n  Ivory-Coast, t h e  Psophoccc-Fus was in t rodu-  
ced i n  1976 i n  two r eg ions  where t h e  annual r a i n f a l l s  are r e s p e c t i v e l y  1500 m 
and 2300 m. Two c u l t i v a r s  were used : one from Fapua (New-Gninea) and one from 
Ghana (of Chinese o r i g i n ) .  
From the beginning,  v i r a l  d i s e a s e s  appeared o n  Lhe Í irst  c u l t u r e s .  Two 
of them w i l l  b e  s u c c e s s i v e l y  descr ibed he re  and t h e  f i rs t  r e s u l c s  of t h e i r  iden-  
t i f i c a t i o n  p resen ted .  
1" Psophocarpus Ringspot Mosa'ic Virus (Pso RSV) 
a) Symptoms : The d i s e a s e  was only observed i n ' t h e  less r a i n y  region.  Every p l a n t  
of each c u l t u r e  was  i n f e c t e d .  The contamination seemed t o  be e a r l y  as the 
symptoms could be  observed on t h e  very f i r s t  leaves. The leaves of t h e  d i s e a s ? ?  
p l a n t s  p re sen ted  l i gh t -g reen  r ingspo t s .  The s p o t s  can or'ten j o i n  t o g e t h e r  t o  
become a yel low mosaïc.  The exact r educ t ion  o f  y i e l d  caused by t h z  d i s e a s e d  i s  
n o t  known b u t  e s t i m a t e d  t o  be about 23 X. As a l l  the p l a n t s  are i n f e c t e d ,  t h e  
t o t a l  l o s s  i s  r a t h e r  severe. 
._.  
b) Transmission : The v i r u s  can e a s i l y  be t r a n s m i t t e d  mechanically from Psopho- 
caqus t o  Psophocaqus, and a l s o  to many o t h e r  hos t -p l an t s  l i s t e d  i n  t a b l e  1. 
It must be n o t i c e d  t h a t  t h e  v i r u s  induces l o c a l  l e s i o n s  on Chenopodizm qz&LQG, 
PhaseoZus mugo and Vigna unguieuZata. Many hos t -p l an t s  react symptomless and 
t h e  v i r u s  o f t e n  produces n e c r o s i s  (Nicotzma cZevc?Zcmdii, N. gZuti.nosa, V<cflU ' 
sinensis, Cqsiewn m~uwn). The v i r u s  cannot i n f s c t  Cucxv&223 ToKato o r  
Chenopodivm amaranticoZor, among o t h e r  nega t ive  h o s i - p l a t s  ( t a b l e  II). I n  
seeds ha rves t ed  Írom n a t u r a l l y  i n f e c t e d  PscpJzoccm?us, t he  t r ansmiss ion  ra te  
of t h e  v i r u s  i s  about 1 2. Aphis craccivora transmit: t h e  @isease i n  the  non- 
p e r s i s t a n t  manner, producing t h e  same symptom. 
1 
! j 
- FAUQUET, c., LAMY, D. & THOUVENEL, J.-C. (1978). TWO 
viral diseases isolated from Winged bean in thé Ivoyy Coast. Communication 
au 7ème Meeting de l'International Working Gryupi on Legume Viruses, 
Zürich, 24-25 août 1978. 
k" Documentaire ORSTOM 
I Cote:B+Rc338 Ex: a- l ~ l ~ ~ ~ ~ ~ ~ l ~ ~ i ~  ~ ~ ~ ~ 1 ~ 1 1  O 1 O0 10738 I - 1  ~ 
P 'I 
I 
,I ' 
C) Bio logica l  p r o p e r t i e s  : The b i o l o g i c a l  p r o p e r t i e s  of t h e  v i r u s  were determined 
i n  the  crude sap of Cnfected Psophocaqms and Chenopodium quinoa. Thermal inac- 
t i v a t i o n  w a s  s i t u a t e d  'between 50" and 55°C. The longevi ty  i n  vitro a t ,  20°C 
ended a t  29 hours aad t h e  v i rus  i s  s t i l l  i n f e c t i o u s  af ter  f reez ing .  
P u r i f i c a t i o n  : '!?he crude sap o f  Psophocarpus i n f e c t e d  leaves i s  c l a r i f i e d  by 
chloroform and t h e  v i r u s  i s  concentrated by alternance of h igh  and low c e n t r i -  
fuga t ions .  The v i r u s  i s  f i n a l l y  p u r i f i e d  on a sucrose  dens i ty  g rad ien t  10-40 % 
during 2 hours .  The y i e l d  of  v i r u s  i s  ab u t  25 mg/kg. P u r i f i e d  p repa ra t ions  of 
the v i r u s  p re sen t  u l t r a v i o l e t  absorp t ion  s p e c t r a  t y p i c a l  of nuc leopro te in  and 
of i some t r i c  p a r t i c l e s ,  w i t h  a A 26C r;m/280 nm r a t i o  of 1.45-1.5. The maximum 
absorp t ion  i s  a t  260 nm and the  minimum a t  243 nmwi th  a r a t i o  of 1.18-1.25. 
In the  l e c t r o n  nxLcroscope, v i rus  p repa ra t ions  nega t ive ly  s t a i n e d  wi th  2 ,5  Z 
uranyl  acetate appeared t o  be composed of s p h e r i c a l  p a r t i c l e s  w i t h  a diamter  
of 24 nm. This p u r i f i e d  suspension inocu la t ed  t o  y o m g  Psoohocarpus induces 
r ingspot  symptoms. 
Serology : The v i r u s  i s  not  a good an t igen  and t h e  serum produced has only a 
t i t r e  of 1/32 i n  g e l  double d i f f u s i o n  t e s t .  The v i r u s  does no t  react wi th  the 
fol lowing antisera : CMV t o ,  CMV d, TAV, TAV 2, TAV ca, PSV 1 and PSV 2. 
Discussion : The d i sease  i s  descr ibed on Psophocarpus f o r  the  f i r s t  t i m e .  Marly 
of i t s  p r o p e r t i e s  l e t  us  th ink  t h e  v i r u s  could be  a cucumovirus. However, 
there are several d i f f e rences  i n  t h e  h o s t  range and symptomatology between 
members o f  the cucumovirus group and t h e  Psophoeaqms Ringspot Virus  (Table III) 
( U R R O U  e t  a l .  1975) e i t h e r  those t h a t  a r e  seed-transmit ted i n  cowpea (ANDERSON 
1975, BRANTLEY 1965, PHATAK e t  a l .  1976, FISCHER 1976) o r  i n  bean (BOS and 
MAAT 1974, BIRD and a l .  197r+J MEINERS and aZ. 1977). None of t h e  s t r a i n s  of 
CMV have been repor ted  t o  produce the  r ingsTo t t ing  symptoms i n  t h e  primary 
leaves of  coqea characteristic of Pso RSV, 
There i s  no s e r o l o g i c a l  r e l a t i o n s h i p  between Pso RSV and members of -- 
t he  CMV group bu t  t h e  cowpea and bean seed-transmitted'strains were no t  t e s t e d ,  
and t h e  lack  of s e r o l o g i c a l  r e l a t i o n s h i p s  does nos exclude t h e  Pso RSV from t h e  
CMV group as f o r  ixistance Cp XSV. 
the molecular weight o f  t h e  p r o t e i n  sudn i t  and the nomber of  nuc le i c  ac ids .  
Virus € o r  the causa l  agent  of the  d isease .  
I n  o rde r  t o  test  t h e  hypothesis ,  it would be  necessary t o  determin 
For the t i m e  being,  we propose t o  keep t h e  name Psophocarpus Ringspot 
2" Psophocarpus Necrot ic  Mosaic Virus (Pso N M V )  
a )  Symptoms : The d i sease  appeared only in t h e  most r a i n y  region. It a f f e c t s  10 Z 
of the  p l a n t s ,  d i s t r i b u t e d  i n  the whcile f i e l d .  The d iseased  leaves  p re sen t  
n e c r o t i c  pa t ches  producing d i s t o r t i o n s  and sometimes w e  can observe a y e l . 1 0 ~  
mosaic on t h e  young leaves .  The su r face  of the leaves i s  very reduced and the 
p l a n t  i s  under6evelopped i n  comparison with t h e  hea l thy  p l a n t s .  The s e v e r i t y  
of d i sease  depends on t h e  e a r l i n e s s  of t h e  a t t a c k .  On young p l a n t s ,  s t r o n g  
a p i c a l  n e c r o s i s  develop aIzd the  winged-bean d i e s .  On o l d e r  p l a n t s ,  t h e  number 
of flowers and consequenLly the  y i e l d  a revery  reduced. . 
Transmission : The disease i s  mechanically transmissible from Z'sophocarpus t o  
Psophocarpus and also t o  a very f imi tzd  host range, belonging t o  legumhoseae 
and Sclanaceae (sec table  IV). The only host-plant presenting symptoms out of 
Psophocaqus i s  CanavaZia e n s i f o m i s ,  the others a re  symptomless. 
The virus i s  not trarismitted e i the r  by seed or  aphid. 
Biological properties : The biological properties o f  the  virus were determined 
i n  the crude sap of infected Psophocarpus and tes ted on seedlings of Psopho- 
carpus. The thermal inact ivat ion point is si tuated between 55" and 60°C, the 
longevity i n  v i t ro  a t  20°C reaches 26 hours and the virus i s  s t i l l  infectious 
a f t e r  14 days congelation. 
Purification : The virus  can be purified e i the r  from CanavaZia ens i fomis  
infected leaves or  from 2Vicoticxa megaZosifon infected leaves. The crude sap 
i s  c la r i f ied  with chloroform and concentrated with ammonium sul fa te .  The f i n a l  
purif icat ion i s  a sucrose density gradient 10 - 40 X during 3 hours. The yield 
of virus i s  about 10 mg/kg. 
The u l t r av io l e t  spectra of purif ied preparations i s  typical  of nucleo- 
protein with an he l i ca l  symetry. The r a t i o  A 260 nm/280 nm = 1.09 ; the maxi- 
mum absorption i s  260 nm and the minimum i s  250 nmwith a r a t i o  OE 1.03. 
observed i n  an electron microscope and revealed elongated par t ic les  with a 
width of 14 nm. The length of the virus i s  varying with the host-plânt and 
i s  614 nm long i n  Nicotiana megazosifon and 645 nm long i n  CanavaZia ensi- 
A purified suspension inoculated t o  yomg seedlings of Psophocarpus 
Virus preparations, negatively stained with 2,5 Z uranyl acetate  were 
formis. 
typical necrosis symptoms. 
Discussion : No such virus i s  known t o  in fec t  the wingsd-3ean and the disease 
i s  described for  the f i r s t  time. Comparing the host-range and symptoms of other  
filamentous viruses infect ing legumes (table V) w e  can f ind no s imi la r i ty  with 
the Psophocarpus necrot ic  mosaic virus. 
properties. 
virus previously undescribed, probably a carlävirus.  W e  propose t o  name it 
Psophocarpus Necrotic Mosaic Virus. 
Besides there i s  no virus described with the same iength and the same 
So w e  think tha t  Psophocarpus Necrosis i s  caused by a filamentous 
CONCLUSION. Since the f i r s t  cultures of winged-bean i n  1976 i n  Ivory-Coast, a t  l ea s t  
two v i r a l  diseases appeared. The f i r s t  one i s  a mosaic with ringspots and i s  
caused by a spherical  virus that  i s  seed and aphid-transmitted. The Psopho- 
carpus Ringspots Mosaic Virus (Pso RSV) i s  probably a cucumo- 
virus ,  a par t icu lar  s t r a i n  of CMV o r  a different  virus.  The second disease 
affecting Psophocarpus i s  a necrotic mosaic the causal agent of which i s  a 
filamentous virus of 620-650 nm. It i s  cer ta inly a new carlavirus infect ing 
leguminosae and we suggest t o  name i t  Psophocarpus Plccrotic Xosaic Virus 
' (Pso NMV). . 
BIBLIOGRAPHY. 
ANDERSON, C.W., 1955 : Vigna and C r o t a Z d a  v i r o s e s  i n  F lo r ida .  I. Pre l imina ry  r e p o r t  
on  a s t ra in  of  Cucumber Xosaic Virus ob ta ined  from cowpea. Plan2 D i s .  Rep t r .  39,  
346-48. 
BIIID, J., 3, SANCIiEZ, R.L. RODRIGlTEZ, A. CORTES-MONLLOR and W. KAISER. 1974. A Eosa ic  
of beans (PhaseoZus vuZgar& L.) caused by a strain of common Oxcurriber Mosaic Vi rus ,  
J. Agr. rJniv. P.R. 58 ( Z ) ,  132-42. 
BLANTLEY, B.B., C.W. KHUN and G. SOWELL, 1965. Effect of Cucumber Mosaic Virus en 
southern  pea  (Vigna sinensis). Amer. Soc. Hort .  Sc i .  87, 355-58. 
BOS, L. and D.Z. MAAT, 1974, A strain of Cucumber Plosaic Virus ,  seed- t ransmi t ted  i n  
beans.  Nether. J. P l a n t .  Path.  80, 113-123. 
FISCHER, H.U., and B.E. LOCKHART. 1976 . A s t r a in  o f  Cucumber Mosaic Virus  i s o l a t e d  
from cowpeas i n  Morocco. Phytopath.  Z. 85, 132-138. 
. =OU, J., J . B .  QUIOT, G. MARCHOUX e t  M. DUTEIL. 1975. C a r a c t é r i s a t i o n  p a r  l a  sympto- 
matologie  de 14 souches du v i r u s  de l a  mosaique du concombre et d e  deux autres cucumo- 
v i r u s  ; tentat ive de c l a s s i f i c a t i o n .  Mede. Fac. Landbouw Rigks. Univ. Gent. 40, 107- 
121. 
NEINJIRS, J.-P., H.E. WATERWORTH, P.F. SMITH, R. ALCONERO and R.H. LAWSON. 1977. A sezd- 
t r a n s m i t t e d  s t r a in  of Cucumber Mosaic Virus  i s o l a t e d  from Bean. The J. Agric .  Univ. 
Puerto-Rico, v o l .  LXI, no  2, 137-147. 
PHATK, H.C., J .R.  DIAZ-RUIZ and R. HULL. 1976. Cowpea Ringspot Vi rus .  A seed-trans- 
m i t t e d  Cucumovirus. Phytopath.  Z., 87, 132-142. 
F amily 
TABLE I 
Chenopodiaceae 
Leguntinosae 
Solanaceae 
Plant  host  t e s t ed  
Chenopodium quinoa 
Phaseohs ZathyroCdes 
Phaseolus mungo 
Phaseolus vulgaris 
Piswn sativwn ' 
Psophocarpus tetragonolobus 
Vicia faba 
Vigna sinensis 
Capsicum annum 
Nicotiana clevelandii 
Nicotiana glutinosa 
Nicotiana megalosiphon 
Nicotiana tubacum samsun 
Petunia hybrida 
Loca l  
it . .  
4 
Y 
4 Y  
Systemic 
43 
@ 
O 
O 
O 
Pos i t ive  hos t -p lan ts  f o r  Psophocar'pus Ring-Spot Virus 
+ Chlorot ic  l e s ion  0 Symptomless 
+ Necrotic l e s ion  Mosafc 
Family 
I 
Chenopodiaceae 
Cucurb itaceae 
Leguminosae 
hlvaceae 
Solanaceae 
Plant-host  t e s t e d  
Beta vulgaris 
Chenopodium maranticolor 
~ 
Cueumis sativus 
Arachis hypogea 
Canavalia ens i fomis  
Cassia occidentalis 
Cassia o le tus i fo l ia  
Centrosema pubescens 
CZitoria rubiginosa 
Cli toria ternatea 
Crotalaria anagyroîdes 
Desmodium lnsiocarpwn 
Glycine m a x  
Phaseolus atropwpwqeus 
T r i  fo Z-Lum repens 
. .  Hibiscus esculentus 
~ ~~ 
Datura s-trmonizun 
Datura innoL~a 
Lycopersicon esculenttun 
Ph y sa l i s  a l ke  kengii 
Physalis floridana 
Solanum melongeîaa . .  
Local 
. . .  
. . . . .  
Sys t ernic 
. . . . .  . . . . . . .  
L 
c 
Negative host-range f o r  Psophoearpus Ring-Spot Virus 
TABLE III 
Arachis hypogea 
Cucumis satiííus 
Datura stramonium 
Lycopersicum escuZentwn 
PhaseoZus vulgaris 
Vigna unguicuZata 
Chenopodium amarantico Zor 
- 
Sero. CMV 
CMV. TAV ?SV C P W  W . P R  
+ - + I +- 9 + 
+ - + + + + + 
+ - c + + + + 
4- + + 4- + 
Iran PF¿ PR Maroc 
+ + - + + + 
CS . . 
- . . . . . . .  . 
Comparaison of hos t - range  of d i f f e r e n t  Cucumo-viruses 
o 
Family 
. TABLE IV 
Leguminosae 
So 1-c eae 
P l a n t - h o s t  t e s t e d  
Arachis hypogea 
CanavaZia ens i fomis  
Hzas eo Zus vu Zgaris 
PhaseoZus ZathyroZdes 
Psophocarcpus te tragono lobus 
Vicia faba 
Nicotiana megazosifon 
Systemic 
O 
O 
O 
O 
O 
P o s i t i v e  hos t - range  f o r  Psophocarpus Necro t i c  Mosaic Virus 
@ mosaic 0 symptomless 
TABLE V 
i 
c 
I 
Family 
Chenopodiaceae 
Cucurbitaceae 
~~ 
Leguminosae 
Malvaceae 
- 
So 1 mac eae 
I 
1 
P l a n t - h o s t  tested 
- 
Beta vulgaris 
Cheno podi  m amarantico lor 
Chenopodium quinoa 
Chenopodium murale. 
C z u m i s  sativus . 
-~ 
Cassia occidentalis 
Cassia oletusi'fozia 
Centroserna pubescens 
CZitoria rubiginosa 
CZitoria ternatea 
Crotalaria anagyroCdes 
Desmodiwn iasiocaqmn 
Glycine max 
PhaseoZus atropurpmzns 
Phas eo lus " g o  
T ~ f o l i w n  repens 
Vigna sinensis 
Hibiscus esculentGs 
-~ 
CapsiCm annum 
Datura innoxfa 
Lycopersicon esculentum 
PhysaZis alkekengii 
Physalis floridana 
Nicotiana clevelandii 
Nicotiana glutinosa 
Nicotiana tabaewn samsun 
Petunia hybrida 
Solunuv melongena 
SoZnnwn nigrum 
- 
Systemic 
- 
Negative host-range f o r  Psophocarpus Necrotic Mosaic Virus 
i- F- - -  - 
m 
p3 
O 
I 
-4 
VI 
O 
VI 
vl 
z 
- 
0 
0 
I 
I 
l 
I 
I 
I 
I 
0 
I 
0 
I 
... 
P V I  o\ o \ o \ - - J m 4  4 4 4 . J - - J L Q -  
C o &  P p 3 V I N V I V I  VI u1 VI < m - o  
O 0  VI O O L n O O  o o o o o v l m  
+ +  I + + + + + I ' + I +  
o s  
c t s r  + I  
4 * *  
- 
Length 
Seed-Borne 
Vector 
Thermo-Inac. 
Geo. dis t r i .  
A1.ach-I-s hypogea 
CanavaZia 
Cassia. 
Chenopodium amarantico lor 
Chenopodiun quinoa 
Cucumis sativus 


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